Heretofore, as an example of a structure for informing a pedestrian or an oncoming vehicle of the speed of a travelling automobile, there has been developed a structure in which a plurality of lights are mounted upon the front surface of hood of a truck, and wherein for example, one light is individually illuminated for each incremento vehicle speed of 20 km/h, however, equipment of this kind is not provided upon other vehicles including automobiles.
Accordingly, a judgment not only by means of a pedestrian but also by means of the operator of an oncoming vehicle was been extremely difficult to make in order determine how fast the approaching vehicle is travelling, and therefore unexpected accidents hace frequently occurred.